JP2893263B2 - Auto Tenshiyona - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auto-tensioner, and more particularly, to adjusting a tension of a timing belt or the like which is hung between a pulley of a crankshaft and a pulley of a camshaft of an automobile engine. Regarding auto tensioner.

2. Description of the Related Art In an automobile engine, a timing belt is used to rotate a crankshaft and a camshaft in synchronization with each other, and an auto-tensioner has been developed for adjusting the tension thereof.

As this type of auto-tensioner, a number of auto-tensioners having a built-in damper mechanism so as not to resonate due to the tension vibration of a belt have been proposed. As an example, a column-shaped fixing member fixed to a fixed portion such as an engine block has been proposed. The movable member on the idler side is rotatably mounted around the idler, high-viscosity oil is interposed between the fixed member and the movable member, and the idler is pressed against the timing belt by a spring provided between the idler and the fixed portion. There is known a device in which an idler moves around a fixing member to adjust the tension of the belt (see Japanese Patent Application Laid-Open No. 62-258252).

According to this auto tensioner, resonance due to tension vibration of the belt can be suppressed by viscous resistance of high-viscosity oil.

Problems to be Solved by the Invention The auto tensioner as described above is mounted on the loose side of the belt, but since the movement of the idler is slow due to the viscous resistance of the oil, when the belt suddenly loosens, There is a problem that it cannot be followed, and a trouble may occur when the engine is suddenly accelerated or stopped. For example, when the engine is stopped, the crankshaft reverses momentarily, and the tension on the slack side of the belt on which the auto tensioner is attached is greatly increased. As a result, the idler may be largely pushed away from the belt by being pushed by the belt, and may stop as it is. Next, when the engine is started, the slack side of the belt suddenly loosens, but when the idler moves largely in the direction away from the belt and stops as described above, the idler cannot follow the sudden loosening of the belt, Timing belt tooth jumps occur, which causes engine trouble.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an auto-tensioner which solves the above-mentioned problem, has a damper function, and can quickly follow a sudden loosening of a belt.

Means for Solving the Problems In the auto tensioner according to the first aspect of the present invention, a columnar idler member on which an idler is rotatably mounted is eccentric around a cylindrical fixed portion side member mounted on the fixed portion. A spring for urging the idler-side member in a direction in which the idler comes into pressure contact with the belt is provided, and the fixed-part-side member is a cylindrical fixed member fixed to the fixed part; In an auto-tensioner in which a member comprises an intermediate annular member rotatably mounted around a fixed member, and a cylindrical movable eccentric member eccentrically and rotatably mounted around the intermediate annular member, In the mutually rotating part of the annular member,
A high friction slide that slides against each other and restricts the mutual rotation of the fixed member and the intermediate annular member when the tension of the belt increases, and allows the mutual rotation of the fixed member and the intermediate annular member when the tension of the belt decreases. A dynamic surface is formed, and a vibration damping means is provided at a portion where the intermediate annular member and the movable eccentric member rotate relative to each other.

The auto-tensioner according to the second aspect of the present invention provides the auto-tensioner according to the first aspect.
In the invention, the vibration damping means is provided with a low friction sliding surface formed so as to slidably contact mutually rotating portions of the intermediate annular member and the movable eccentric member, and is interposed between these low friction sliding surfaces. Of high viscosity oil.

In the auto-tensioner according to the third aspect of the present invention, a cylindrical idler-side member on which an idler is rotatably mounted is eccentrically and rotatably mounted around a cylindrical fixed-part-side member mounted on the fixed portion. A spring is provided for urging the idler-side member in a direction in which the idler is pressed against the belt, and the fixed-part-side member is rotatably mounted around the cylindrical fixed member fixed to the fixed part, and the fixed member. In an auto-tensioner comprising a cylindrical movable eccentric member eccentrically and rotatably mounted around the intermediate annular member, the idler-side member rotates the intermediate annular member and the movable eccentric member mutually. When the belt is in sliding contact with the moving part and the tension of the belt increases, the rotation of the intermediate annular member and the movable eccentric member is restricted. The intermediate annular member and the high friction sliding surface to allow mutual rotation of the movable eccentric member is formed, the portion which rotates with each other of the fixing member and the intermediate annular member when a little,
A vibration damping means is provided.

The auto-tensioner according to the invention of claim 4 provides the auto-tensioner according to claim 3
In the invention, the vibration damping means is interposed between the low friction sliding surfaces formed so as to be in sliding contact with the mutually rotating portions of the fixed member and the intermediate annular member, and is interposed between these low friction sliding surfaces. Made of high-viscosity oil.

In the invention of claim 1, when the vertical load is large between the fixed member and the high friction sliding surface of the intermediate annular member,
Slip does not occur because the static friction is large, but when the vertical load is small, the static friction is also small, so that slip is likely to occur.

When the tension of the belt increases, the idler side member receives a large radial load from the belt via the idler, so that the vertical load between the fixed member and the high friction sliding surface of the intermediate annular member increases, and these increase the static friction. And the fixing member and the intermediate annular member do not rotate with each other. Then, as the movable eccentric member rotates with respect to the intermediate annular member, the idler moves in a direction to decrease the tension, and the tension is maintained at a predetermined value. At this time, the damping effect is exerted by the vibration damping means provided at the mutually rotating portions of the intermediate annular member and the movable eccentric member.

When the belt tension decreases, the radial load from the belt on the idler side member decreases, so that the vertical load between the fixed member and the high friction sliding surface of the intermediate annular member decreases, and these surfaces mutually It becomes easy to slip. For this reason, the idler-side member is quickly rotated by the elastic force of the spring, and the idler quickly follows the slack of the belt, and the tension is maintained at a predetermined value.

According to a second aspect of the present invention, the vibration damping means of the first aspect of the present invention is provided with a low friction sliding surface formed so as to slidably contact mutually rotating portions of the intermediate annular member and the movable eccentric member. Since it is made of high-viscosity oil interposed between low friction sliding surfaces, a high damper effect is exhibited,
In addition, the belt tension can be maintained at a predetermined value. That is, for example, when the tension is slowly increased due to a temperature change, the low friction sliding surface of the intermediate annular member and the low friction sliding surface of the movable eccentric member can slide with each other, and the movable eccentric member reduces the belt tension. By rotating slowly in the decreasing direction, the tension is maintained at a predetermined value. On the other hand, for high-frequency vibration loads such as belt vibration, the viscous resistance due to oil between the low friction sliding surface of the intermediate annular member and the low friction sliding surface of the movable eccentric member increases, and these are reduced. Since the mutual eccentric members are less likely to slip, rotation of the movable eccentric member is suppressed, and a high damper effect is exhibited.

In the invention of claim 3, between the intermediate annular member and the high friction sliding surface of the movable eccentric member, when the vertical load is large, the static friction is large, so that no slip occurs, but when the vertical load is small, the static friction is also small. Since it is smaller, slip is likely to occur.

When the tension of the belt increases, the idler-side member receives a large radial load from the belt via the idler, so that the vertical load between the intermediate annular member and the high friction sliding surface of the movable eccentric member increases. The intermediate annular member and the movable eccentric member do not rotate with each other because they are fixed to each other by static friction. Then, as the intermediate annular member rotates relative to the fixed member, the idler moves in a direction to decrease the tension, and the tension is maintained at a predetermined value. At this time, the damping effect is exerted by the vibration damping means provided at the mutually rotating portions of the intermediate annular member and the fixed member.

When the belt tension decreases, the radial load from the belt on the idler member decreases, so that the vertical load between the intermediate annular member and the high friction sliding surface of the movable eccentric member decreases, and these surfaces are mutually It becomes easy to slip. For this reason, the idler-side member is quickly rotated by the elastic force of the spring, and the idler quickly follows the slack of the belt, and the tension is maintained at a predetermined value.

According to a fourth aspect of the present invention, the vibration damping means of the third aspect of the present invention is provided with a low friction sliding surface formed so as to slidably contact mutually rotating portions of the fixed member and the intermediate annular member. Since it is made of high-viscosity oil interposed between the friction sliding surfaces, a high damper effect is exhibited as described above, and the belt tension can be maintained at a predetermined value.

Hereinafter, an embodiment in which the present invention is applied to a timing belt hung between a crankshaft and a camshaft of an automobile engine will be described with reference to the drawings.

1 to 4 show a first embodiment, and FIG. 5 shows an enlarged view of a main part thereof.

Fixed parts of the engine (eg engine block)
In (10), a columnar fixing member (11) is attached to one bolt (1).
It is fixed by 2). The fixing member (11) includes a shaft portion (13) on the side of the fixing portion (10) (proximal side) and a plate portion (14) on the opposite side (distal side).
Has been fixed by. Flanges (13a) (14a) are formed integrally with the intermediate portion of the shaft portion (13) and the plate portion (14), respectively, and the flanges (13a) (1
A high friction sliding surface (11a) is formed on the outer periphery of the portion between 4a). This high friction sliding surface (11a) is
1) may be made of a material having a high coefficient of friction such as steel and formed directly on the outer peripheral surface thereof, or may be formed by fixing or coating a high friction material on the outer peripheral surface of the fixing member (11). Good.

An intermediate sleeve (intermediate annular member) (16) is rotatably mounted around the high friction sliding surface (11a) of the fixed member (11). Sleeve (16) is the inner high friction material (17)
And a low friction material (18) fixed to the outer peripheral surface thereof. The high friction material (17) is made of steel or other material having a high coefficient of friction, and its inner peripheral surface has a high friction sliding surface (17).
a). The low friction material (18) is made of a fluororesin or other material having a low friction coefficient, and its outer peripheral surface is a low friction sliding surface (18a). The sleeve (1
The outer diameter of the outer peripheral surface of 6), that is, the low friction sliding surface (18a) is smaller than the outer diameter of the flanges (13a) and (14a) of the fixing member (11). The width of the low friction material (18) is slightly smaller than the width of the high friction material (17).

A short cylindrical movable eccentric member (19) is eccentric and rotatable around the low friction sliding surface (18a) of the sleeve (16) between the flanges (13a) and (14a) of the fixing member (11). Mounted on A low friction sliding surface (19a) is formed on the inner peripheral surface of the eccentric member (19). This low friction sliding surface (19a)
May be formed directly on the inner peripheral surface of the eccentric member (19),
It may be formed by fixing or coating a low friction material on the inner peripheral surface of the eccentric member (19). Sleeve (16)
Between the low friction sliding surface (18a) and the low friction sliding surface (19a) of the eccentric member (19), for example, viscosity 100,000 cst (25 ° C)
The above silicone oil (0) is interposed.
An O-ring (20) for sealing oil (0) is provided between the outer peripheral surface of the high friction material (17) on both sides of the low friction material (18) of the sleeve (16) and the eccentric member (19). Is provided.

A cylindrical idler (21) is rotatably mounted around the eccentric member (19) via a plurality of spherical rolling elements (22).

Two pins (23) and (24) parallel to the axis are fixed to the eccentric member (19). The first pin (23) protrudes from the eccentric member (19) on both sides, and a portion protruding toward the distal end side serves as a stopper (23a). The second pin (24) protrudes only from the eccentric member (19) to the proximal end side. A torsion coil spring (25) is mounted around a portion of the shaft (13) of the fixing member (11) closer to the base end than the flange (13a). One end (25a) of the spring (25) is connected to the second pin (24) of the eccentric member (19), and the bent portion (25b) near the end (25a) is connected to the first pin of the eccentric member (19). (twenty three)
Respectively, and the other end (25c) is a fixing member (10)
Hooked on the third pin (26) fixed to the second pin. And
This spring (25) is used to connect the eccentric member (19) to the eccentric member (19) in FIGS.
The idler (21) is pressed against the surface of the timing belt (27) on the loose side of the timing belt (27) without teeth (28) by urging in the counterclockwise direction in the figure.

Approximately half the circumference of the flange (14a) of the plate portion (14) of the fixing member (11) is a large diameter portion (14b), and the remaining approximately half circumference is a small diameter portion (14c). The rotation range of the eccentric member (19) is restricted by contact of the stopper portion (23a) of the pin (23) with both circumferential ends of the large-diameter portion (14b). In the operating state, the stopper portion (23a) of the first pin (23) is located at the center in the circumferential direction of the small diameter portion (14c) of the flange (14a). Thus, the eccentric member (19) can rotate in any direction.

In this case, the fixed member (11) forms a fixed portion side member, and the sleeve (16) and the eccentric member (19) form an idler side member. In addition, the low friction sliding surface (18a) of the sleeve (16) and the low friction sliding surface (1
9a) and the oil (0) therebetween constitute a vibration damping means.

 Next, the operation of the above-described auto tensioner will be described.

Between the high-friction sliding surface (17a) of the sleeve (16) and the high-friction sliding surface (11a) of the fixing member (11) in contact therewith,
When the vertical load is large, slip does not occur because the static friction is large. However, when the vertical load is small, the static friction is also reduced, so that the slip easily occurs. On the other hand, slippage occurs between the low-friction sliding surface (18a) of the sleeve (16) and the low-friction sliding surface (19a) of the eccentric member (19) in contact with the sleeve regardless of the magnitude of the vertical load. Since the high-viscosity oil (0) is interposed between them, the slip is gentle.

When the tension of the belt (27) increases, the eccentric member (19)
Receives a large radial load from the belt (27) via the idler (21), so that the high friction sliding surface (17a) of the sleeve (16) and the high friction sliding surface ( 11a), the vertical load between them increases, they are fixed to each other by a large static friction, and the sleeve (16) does not rotate. Then, the low friction sliding surface (18
a) and the low friction sliding surface (19) of the eccentric member (19)
Due to the viscous drag of the high viscosity oil (0) between a)
When the damper effect is exhibited, that is, when the tension changes slowly due to, for example, temperature change, the low friction sliding surface (18a) of the sleeve (16) and the low friction sliding surface (19a) of the eccentric member (19). Can slide with each other, and the eccentric member (19) slowly rotates clockwise in FIG. 2 against the spring (25) due to the radial load from the belt (27). For this reason,
The idler (21) moves slowly in the direction to decrease the tension, and the tension is maintained at a predetermined value. On the other hand, for high-frequency vibration load such as belt vibration, the sleeve (1
The viscous damping coefficient due to the oil (0) between the low friction sliding surface (18a) of (6) and the low friction sliding surface (19a) of the eccentric member (19) becomes large, so that they are less likely to slip mutually. Therefore, rotation of the eccentric member (19), that is, movement of the idler (21) is suppressed, and a damper effect is exhibited.

When the tension of the belt (27) decreases, the eccentric member (19)
As the radial load from the belt (27) is reduced, the friction between the high friction sliding surface (17a) of the sleeve (16) and the high friction sliding surface (11a) of the fixing member (11) in contact with the sleeve (16) is reduced. Normal loads and static friction are reduced, making them easier to slip on each other. On the other hand, the low-friction sliding surface (18a) of the sleeve (16) and the low-friction sliding surface (19a) of the eccentric member (19) in contact with the sleeve have a large viscosity of the high-viscosity oil (0) between them. Although it is difficult to slip due to the damping coefficient,
High friction sliding surface (17a) of sleeve (16) and fixing member (1
Since the high friction sliding surface (11a) of 1) is easy to slide as described above, the eccentric member (19) and the sleeve (16) are fixed to the fixed member (11) by the elastic force of the spring (25). On the other hand, it rotates quickly in the counterclockwise direction in FIG. Therefore, the idler (21) moves quickly in the direction approaching the belt (27), and quickly follows the loosening of the belt (27).

Therefore, when the engine is stopped and then started,
Even if the slack side of the belt (27) is suddenly loosened, the belt (27) can be quickly followed to prevent tooth jump of the belt (27).

 FIG. 6 shows a modification of the intermediate sleeve (16).

The sleeve (16) includes a core material (30), a high friction material (31) fixed to the inner peripheral surface of the core material (30), and a low friction material (31) fixed to the outer peripheral surface of the core material (30). 32). The core (30) is made of a suitable material such as steel. Then, the inner peripheral surface of the high friction material (31) has a high friction sliding surface (31a),
The outer peripheral surface of the low friction material (32) is a low friction sliding surface (32a). Also, the low friction sliding surface (32a) of the sleeve (16)
The silicone oil (0) is interposed between the low friction sliding surface (19a) of the eccentric member (19) and the outer peripheral surface of the core material (30) on both sides of the low friction material (32) of the sleeve (16). An O-ring (20) is provided between the eccentric member (19) and the eccentric member (19).

Other parts are the same as those in FIGS. 1 to 5, and the same parts are denoted by the same reference numerals.

 FIG. 7 shows another modification of the intermediate sleeve (16).

The sleeve (16) is composed of an outer high friction material (33) and a low friction material (34) fixed to the inner peripheral surface, and the outer peripheral surface of the high friction material (33) is Moving surface (33a),
The inner peripheral surface of the low friction material (34) is a low friction sliding surface (34a). Correspondingly, a low friction sliding surface (11b) is formed on the outer peripheral surface of the fixed member (11), and a low friction sliding surface (19b) is formed on the inner peripheral surface of the eccentric member (19). In (16), silicone oil (0) is interposed between the low friction sliding surface (34a) and the low friction sliding surface (11b) of the fixing member (11). Also, between the inner peripheral surface of the high friction material (33) on both sides of the low friction material (34) of the sleeve (16) and the fixing member (11),
An O-ring (20) is provided.

In this case, the fixed member (11) and the sleeve (16) form a fixed part side member, and the eccentric member (19) forms an idler side member. In addition, the low friction sliding surface (11b) of the fixing member (11) and the low friction sliding surface (3
The vibration damping means is constituted by 4a) and the oil (0) therebetween.

The operation of the auto tensioner in this case is as follows.

When the tension of the belt (27) increases, the eccentric member (19)
Receives a large radial load from the belt (27) via the idler (21), the high friction sliding surface (33a) of the sleeve (16) and the high friction sliding surface (33) of the eccentric member (19) in contact with it 19b), the vertical load between them increases, they are fixed to each other by a large static friction, and the sleeve (16) and the eccentric (19) do not rotate relative to each other. The viscous resistance of the high-viscosity oil (0) between the low-friction sliding surface (34a) of the sleeve (16) and the low-friction sliding surface (11b) of the fixing member (11) in contact with the sleeve (16) causes the damper to move. The effect is exhibited. That is, in the case of a slow tension change due to, for example, a temperature change, the low friction sliding surface (34a) of the sleeve (16) and the low friction sliding surface (11b) of the fixing member (11) can slide with each other. The eccentric member (19) and the sleeve (16) are
Due to the radial load from 7), it rotates gently against the spring (25). Therefore, the idler (21) moves gently in the direction to decrease the tension, and the tension is maintained at a predetermined value. On the other hand, for a high-frequency vibration load such as belt vibration, the oil between the low-friction sliding surface (34a) of the sleeve (16) and the low-friction sliding surface (11b) of the fixing member (11). The viscous damping coefficient due to (0) becomes large, and it becomes difficult for these to slip mutually. Therefore, rotation of the eccentric member (19) and the sleeve (16), that is, movement of the idler (21) is suppressed, and a damper effect is exhibited.

When the tension of the belt (27) decreases, the eccentric member (19)
As the radial load from the belt (27) is reduced, the high friction sliding surface (34a) of the sleeve (16) and the high friction sliding surface (19b) of the eccentric member (19) in contact with it Normal loads and static friction are reduced, making them easier to slip on each other. On the other hand, the low-friction sliding surface (34a) of the sleeve (16) and the low-friction sliding surface (11b) of the fixed member (11) in contact with the sleeve (16) correspond to the high viscosity oil (0) between them. Although it is difficult to slip due to the damping coefficient,
High friction sliding surface (33a) of sleeve (16) and eccentric member (1
Since the high friction sliding surface (19b) of (9) is easy to slide as described above, the eccentric member (19) is quickly rotated by the elastic force of the spring (25). Therefore, the idler (21) moves quickly in the direction approaching the belt (27), and quickly follows the loosening of the belt (27).

Other parts are the same as those in FIGS. 1 to 5, and the same parts are denoted by the same reference numerals.

FIG. 8 shows another modification of the intermediate sleeve (16).

The sleeve (16) is composed of a core material (35), a low friction material (36) fixed to the inner peripheral surface of the core material (35), and a high friction material (36) fixed to the outer peripheral surface of the core material (35). 37), the inner peripheral surface of the low friction material (36) is a low friction sliding surface (36a), and the outer peripheral surface of the high friction material (37) is a high friction sliding surface (37a). I have. Also, silicone oil (0) is interposed between the low friction sliding surface (36a) of the sleeve (16) and the low friction sliding surface (11b) of the fixing member (11), and the low friction of the sleeve (16) is provided. Inner peripheral surface of core material (35) on both sides of material (36) and fixing member (11)
And an O-ring (20).

Other parts are the same as those in FIG. 7, and the same parts are denoted by the same reference numerals.

5 and 7, the low friction material (18) (34) is fixed to the high friction material (17) (33), but the low friction material is thinly coated on the surface of the high friction material. Is also good. 6 and 8, the high friction materials (31) and (37)
Although the low friction materials (32) and (38) are fixed to the surfaces of the core members (30) and (35), the high friction material and the low friction material may be thinly coated on the surface of the core material.

9 to 12 show a second embodiment, and FIG. 13 shows an enlarged view of a main part thereof.

A cylindrical fixing member (4
1) is fixed by one bolt (42). The fixing member (41) includes a first shaft portion (43) on the proximal end side and a second shaft portion (44) on the distal end side, and these are fixed by press-fitting. Outward flanges (43a) and (44a) are integrally formed at the tip portions of the two shaft portions (43) and (44), respectively, and the outer peripheral edges of these flanges (43a) and (44a) approach each other. Short cylindrical overhang (43
b) and (44b) are integrally formed. And
The inner peripheral surfaces of these overhangs (43b) (44b) are high friction sliding surfaces (41a).

An intermediate annular member (45) is rotatably mounted in an annular space between the two flanges (43a) (44a) around the second shaft portion (44) of the fixing member (41). Annular member (45)
Are outward flanges (45b) on both ends of the cylindrical part (45a)
(45c) is formed. The first flange (45b) on the distal end is formed integrally with the cylindrical portion (45a), while the second flange (45c) on the proximal end is separately formed and fixed to the cylindrical portion (45a). I have. The inner diameter of the cylindrical portion (45a) of the annular member (45) is equal to the second shaft portion (44) of the fixing member (41).
Is slightly larger than the outside diameter of these, and there is a gap between them.
A high friction material (46) is fixed to the outer peripheral surface of the two flanges (45b) (45c) of the annular member (45), and the outer peripheral surface is a high friction sliding surface (46a). Cylindrical part (4
A low friction material (47) is fixed to the outer peripheral surface of 5a), and the outer peripheral surface is a low friction sliding surface (47a).

A short columnar movable eccentric member (48) is eccentrically and rotatably mounted around the cylindrical portion (45a) between the flanges (45b) and (45c) of the annular member (45). Eccentric member (4
A low friction sliding surface (48a) is formed on the inner peripheral surface of 8). For example, the viscosity between the low friction sliding surface (47a) of the annular member (45) and the low friction sliding surface (48a) of the eccentric member (48) is 1
A silicone oil (0) of not less than 00,000 cst (25 ° C.) is interposed. An O-ring (49) for sealing oil (0) is provided between the flanges (45b) (45c) on both sides of the annular member (45) and both end faces of the eccentric member (48).

A cylindrical idler (50) is rotatably mounted around the eccentric member (48) via a plurality of spherical rolling elements (51).

At the base end of the fixing member (41), a bracket (52)
The short cylindrical portion (52a) is fitted by appropriate means such as press fitting. The bracket (52) is integrally formed with an engaging portion (52b) extending long upward, and at the tip thereof,
An engagement hole (54) into which the engagement pin (53) fixed to the fixing portion (10) fits is formed. Right-angled bent portions (52c) and (52d) are integrally formed at the tips of the portions protruding from the two portions on the side of the bracket (52), so that the force for rotating the bracket (52) during assembly is formed. A load acting portion (55) for applying the pressure is formed. In addition, the fixing member (11) has substantially the engagement hole (5) of the bracket (52).
Slotted bolt holes (5) extending circumferentially around 4)
6) is formed.

Two pins (57) and (58) parallel to the axis are fixed to the eccentric member (48). These pins (57)
(58) protrudes to both sides from the eccentric member (48). A torsion coil spring (59) is mounted around a portion of the fixing member (41) closer to the base end than the flange (43a) of the first shaft portion (43). One end (59a) of the spring (59) is connected to the second pin (58) of the eccentric member (48), and the bent portion (59b) near the end (59a) is connected to the first pin of the eccentric member (48). (57), and the other end (59c) is hung on a notch (60) formed on the outer periphery of the base end of the first shaft (43). The spring (59) urges the eccentric member (48) in the counterclockwise direction in FIGS. 10 and 11, and the idler (50) causes the timing belt (61) to loosen the teeth (62) on the loose side. Mounted on a non-existent surface.

Flange (44a) of second shaft part (44) of fixing member (41)
The projections (63) are integrally formed at two places on the outer peripheral edge of the eccentric member (48). The two pins (57) and (58) of the eccentric member (48) hit these projections (63), and thus the eccentric member (48) is formed. Is restricted. In addition, an indicator mark (64) is provided at a circumferentially central portion between the protrusions (63) of the flange (44a) of the second shaft portion (44),
In the operating state, the mark (64) is located between the two pins (57) and (58) so that the eccentric member (19) can rotate in any direction with respect to the fixing member (41). Has become.

The operation of the auto tensioner of the second embodiment is the same as that of the first embodiment.

That is, when the tension of the belt (61) increases, the eccentric member (48) receives a large radial load from the belt (61) via the idler (50), and thus the high friction sliding surface of the annular member (45). The vertical load between (46a) and the high friction sliding surface (41a) of the fixed member (41) in contact therewith increases,
These are fixed to each other by a large static friction, and the annular member (45) and the fixing member (41) do not rotate with each other. And
Due to the viscous resistance of the high-viscosity oil (0) between the low-friction sliding surface (47a) of the annular member (45) and the low-friction sliding surface (48a) of the eccentric member (48) in contact with the annular member (45), the damper effect is obtained. Is exhibited.

When the tension of the belt (61) decreases, the eccentric member (48)
Between the high friction sliding surface (46a) of the annular member (45) and the high friction sliding surface (41a) of the fixed member (41) in contact with the annular member (45) because the radial load from the belt (61) is reduced. The vertical load and the static friction are reduced, and they are liable to slip with each other. For this reason, the eccentric member (48) is quickly rotated by the elastic force of the spring (59), and the idler (50) is quickly moved in the direction approaching the belt (61), so that the belt (61) is quickly loosened. To follow.

In the case of the second embodiment, the flange (45) of the annular member (45) is used.
b) Since the high friction sliding surface (46a) is formed on the outer periphery of (45c), the diameter of the high friction sliding surface (46a) increases,
When a vertical load is applied, the frictional resistance works reliably.

 FIG. 14 shows a modification of the annular member (45).

On the outer periphery of the flanges (45b) (45c) of the annular member (45), tapered surfaces (65) facing each other are formed,
A high friction material (46) is fixed to the tapered surface (65). In addition, the high friction sliding surface (41a) of the projecting portions (43b) (44b) of the fixing member (41) is also the tapered surface (6) of the annular member (45).
It is formed in a tapered shape corresponding to 5).

In this case, since the high-friction sliding surfaces (46a) of the annular member (45) are tapered in opposite directions, the area of the high-friction sliding surfaces (46a) increases by that much, and furthermore, the tapered surface is increased. Since the surface pressure is increased by the wedge action of, the frictional resistance can be further increased.

According to the auto tensioner of the present invention, as described above, when the tension of the belt increases, the fixed member and the intermediate annular member or the intermediate annular member and the movable eccentric member do not rotate with each other, and When the damping effect is exerted by the damping means and the belt tension is reduced, the high friction sliding surfaces of the fixed member and the intermediate annular member, or the high friction sliding surfaces of the intermediate annular member and the movable eccentric member are easily slipped with each other. Due to the elastic force of the spring, the idler-side member rotates quickly, and the idler quickly follows the loosening of the belt. Therefore,
The vibration of the belt is attenuated, and the resonance due to the tension vibration of the belt can be suppressed. Further, when the belt tension is reduced, the idler-side member rotates quickly, and the idler quickly follows the belt loosening, thereby preventing the timing belt from jumping and preventing engine trouble. it can.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view (a sectional view taken along line II of FIG. 2) of an auto tensioner showing a first embodiment of the present invention, and FIG.
FIG. 3 is a sectional view taken along the line III-III of FIG. 1, FIG. 4 is a sectional view taken along the line IV-IV of FIG. 1, and FIG. 5 is an intermediate sleeve of FIG. FIG. 6 is a longitudinal sectional view showing an enlarged part, FIG. 6 is a drawing corresponding to FIG.
The drawing is a drawing corresponding to FIG. 5 showing another modification of the intermediate sleeve, and FIG. 8 is a fifth drawing showing still another modification of the intermediate sleeve.
FIG. 9 is a longitudinal sectional view (a sectional view taken along the line IX-IX in FIG. 10) of the auto-tensioner showing the second embodiment, FIG. 10 is a sectional view taken along the line XX in FIG. 11 is a sectional view taken along the line XI-XI of FIG. 9, FIG. 12 is a sectional view taken along the line XII-XII of FIG. 9, and FIG. 13 is a longitudinal sectional view showing an enlarged portion of the intermediate annular member of FIG. Figure, No.
FIG. 14 is a drawing corresponding to FIG. 13 showing a modification of the intermediate annular member. (10) (40): Fixed member, (11) (41): Fixed member, (16): Intermediate sleeve (intermediate annular member), (17)
a) (31a) (33a) (37a) (46a) ... high friction sliding surface,
(18a) (32a) (34a) (36a) (47a) ... low friction sliding surface, (19) (48) ... movable eccentric member, (21) (50) ...
Idler, (25) (59) ... Torsion coil spring, (27)
(61) ... timing belt, (45) ... middle annular member.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-303252 (JP, A) JP-A-58-72757 (JP, A) JP-A-64-58846 (JP, A) 188652 (JP, U) Japanese Utility Model Showa 57-175845 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) F16H 7/00-7/24

Claims (4)

(57) [Claims] A cylindrical idler side member having an idler rotatably mounted thereon is eccentrically and rotatably mounted around a cylindrical fixed portion side member mounted on the fixed portion, and the idler is attached to the belt. A spring for urging the idler-side member in the pressing direction is provided, and the fixed-part-side member is a cylindrical fixed member fixed to the fixed part, and the idler-side member is rotatably mounted around the fixed member. An auto-tensioner comprising an intermediate annular member provided and a cylindrical movable eccentric member eccentrically and rotatably mounted around the intermediate annular member, wherein the mutually rotating portions of the fixed member and the intermediate annular member slide on each other. When the tension of the belt increases, the rotation of the fixing member and the intermediate annular member is restricted, and when the tension of the belt decreases, the fixing member and the intermediate annular member decrease. An auto-tensioner, wherein a high friction sliding surface which allows mutual rotation is formed, and a vibration damping means is provided at a part of the intermediate annular member and the movable eccentric member which rotate mutually. 2. A low friction sliding surface formed so that the vibration damping means is in sliding contact with a mutually rotating part of the intermediate annular member and the movable eccentric member, and interposed between these low friction sliding surfaces. 2. The auto-tensioner according to claim 1, wherein the auto-tensioner is made of a high-viscosity oil. 3. A cylindrical idler side member having an idler rotatably mounted thereon is eccentrically and rotatably mounted around a cylindrical fixed portion side member mounted on the fixed portion, and the idler is mounted on the belt. A spring for urging the idler-side member in the direction of pressing is provided, and the fixed-part-side member is formed of a cylindrical fixed member fixed to the fixed portion, and an intermediate annular member rotatably mounted around the fixed member. Wherein the idler-side member is an auto-tensioner comprising a cylindrical movable eccentric member eccentrically and rotatably mounted around the intermediate annular member, wherein the intermediate annular member and the movable eccentric member rotate relative to each other,
When the belt is in sliding contact with each other and the tension of the belt increases, the intermediate annular member and the movable eccentric member are restricted from rotating relative to each other, and when the tension of the belt is reduced, the intermediate annular member and the movable eccentric member are allowed to rotate relative to each other. A friction sliding surface is formed, and in the mutually rotating part of the fixed member and the intermediate annular member,
An automatic tensioner provided with vibration damping means. 4. A low friction sliding surface formed so that the vibration damping means is in sliding contact with the mutually rotating portions of the fixed member and the intermediate annular member, and is interposed between these low friction sliding surfaces. 4. The auto-tensioner according to claim 3, wherein the auto-tensioner is made of a high-viscosity oil.